In another thread the subject of breathing patterns and buoyancy control came up. Unfortunately when I tried to split the relevant posts off (Apologies to NWGratefulDiver and Marek K), I deleted them in the process.
Anyway, the basic question was whether the the slow, deep breathing pattern we're taught to use or a short shallow breathing pattern was more conducive to good buoyancy control, and why...
Here's my take (excerpt from my posts on buoyancy about four years ago)
---
Let’s examine the dynamics of a displacement from neutral to see how to use breathing for fine tuning buoyancy control. As a starting point, let’s assume we have achieved perfect neutral buoyancy with half a breath in our lungs. If we are displaced upwards, we will rise until we provide a counterforce to stop the rise. So, we begin to exhale as we start upward, and continue to exhale until our upward movement has stopped. Remembering that an object in motion will remain in motion until a force in the opposite direction is applied, we must have exhaled enough to have applied a downward force – we have become negatively buoyant - to get our ascent to stop, and so if we do nothing at this point we will begin to sink. And as we sink gasses in our body and BC will compress and we’ll continue to sink unless we do something to counter it – inhale. But this “exhale while rising, inhale while sinking” doesn’t keep us stationary does it? To achieve near stability, we must get back to neutral as soon as we stop at a desired depth, so it goes something like this… As we are descending we inhale to stop the descent; as we come to a stop, we must immediately exhale to get neutral, because in order to stop the descent we had to get positive. Continuing to exhale, we will eventually become negative again, and need to inhale before a descent can start, then exhale before an ascent can start, and so forth. With a great deal of practice, we will find that we can breathe slowly and deeply without ever making any noticeable vertical excursions at all!
---
Rick
Anyway, the basic question was whether the the slow, deep breathing pattern we're taught to use or a short shallow breathing pattern was more conducive to good buoyancy control, and why...
Here's my take (excerpt from my posts on buoyancy about four years ago)
---
Let’s examine the dynamics of a displacement from neutral to see how to use breathing for fine tuning buoyancy control. As a starting point, let’s assume we have achieved perfect neutral buoyancy with half a breath in our lungs. If we are displaced upwards, we will rise until we provide a counterforce to stop the rise. So, we begin to exhale as we start upward, and continue to exhale until our upward movement has stopped. Remembering that an object in motion will remain in motion until a force in the opposite direction is applied, we must have exhaled enough to have applied a downward force – we have become negatively buoyant - to get our ascent to stop, and so if we do nothing at this point we will begin to sink. And as we sink gasses in our body and BC will compress and we’ll continue to sink unless we do something to counter it – inhale. But this “exhale while rising, inhale while sinking” doesn’t keep us stationary does it? To achieve near stability, we must get back to neutral as soon as we stop at a desired depth, so it goes something like this… As we are descending we inhale to stop the descent; as we come to a stop, we must immediately exhale to get neutral, because in order to stop the descent we had to get positive. Continuing to exhale, we will eventually become negative again, and need to inhale before a descent can start, then exhale before an ascent can start, and so forth. With a great deal of practice, we will find that we can breathe slowly and deeply without ever making any noticeable vertical excursions at all!
---
Rick
